Releasing device for the locking mechanism in wire line core drills

ABSTRACT

This invention relates to a releasing device for disconnecting a locking mechanism for a catching device which serves for connecting the wire with the inner core tube in wire line core drills, the locking mechanism having a gripper head connected with the wire, the gripper head being provided with a locking shoulder to engage with a latch, a releasing sleeve being provided to release the locking shoulder by applying a predetermined pulling force to the wire.

References Cited UNITED STATES PATENTS United States Patent [72]Inventor Oyvind Jensen Stockholm Sv, Sweden [21] Appl. No. 835,965

[22] Filed June 24,1969 [45] Patented Oct. 5, 1971 [73] Assignee AtlasCopco Aktiebolag Nacka, Sweden July 2, 1968 Sweden [32] Priority [54]RELEASING DEVICE FOR THE LOCKING MECHANISM IN WIRE LINE CORE DRILLS 2Claims, 10 Drawing Figs.

[51] Int Cl 294/86.19, 294/862 ....E2lb3l/00, E21c 19/00 FIG. 3A

0 352 7 2 3 44M J0 4 Md 3 i SHEET 1 BF 3 ll lltll- PATENIEU [1m 519mFIG. 7

RELEASING DEVICE FOR THE LOCKING MECHANISM IN WIRE LINE CORE DRILLS Thepresent invention relates to a releasing device for disconnecting alocking mechanism for a catching device which serves for connecting thewire with the inner core tube in wire line core drills thereby enablinglifting and also lowering of the inner core tube, the locking mechanismhaving a gripper head connected with the wire, the gripper head beingprovided with a locking shoulder behind which a latch connected with theinner core tube is intended to engage and lock in order to perform saidconnection.

In lifting the inner core tube in wire line core drills a catchingdevice is used which is lowered down in the borehole and being intendedto engage a gripper means on the upper end of the inner tube. However,it may occur that the inner tube for some reason jams in the outer tube,and once when the catching device has engaged the gripper means there isnot any possibility of releasing the catching device without lifting theentire bore tube. Besides the wire has then to be cut off since itotherwise hinders the disassembling of the lifted bore tubes.

The object of this invention is to provide a device which enables thecatching device to be released from locking engagement also in caseswhen the inner tube jams in the outer tube and, thus, cannot be pickedup. Thus, at least the catching device and the wire can be picked up,whereupon other steps must be taken to continue the work.

The releasing device according to the invention is substantiallycharacterized by a releasing sleeve which in its normal rest position isbrought back a distance from the locking shoulder of the gripper head torelease the locking shoulder, the releasing sleeve being retainable inthis position by means of a positioning mechanism which is releasable byapplying a predetermined pulling force to the wire, said pulling forcehaving a direction from the inner core tube and exceeding the weight ofthe inner core tube. Upon releasing of the positioning mechanism thesleeve is provided to be displaced unobstructedly towards the gripperhead and to engage the locking shoulder of the gripper head, therebymoving away the latch.

The present invention will now be described in more detail, by way ofexample, with reference to the accompanying drawings. Like referencesrefer to like or similar parts throughout the drawings. In allembodiments shown and described the tubes and housings may be joined byscrew threading.

FIG. I is a cross-sectional view of an embodiment of the releasingdevice in accordance with the invention, illustrating particularly agripper head and locking means.

FIGS. 2A, 2B and 2C are illustrating the operational sequence forreleasing the sliding sleeve from a locked position (with active lockingmeans) to a free position.

FIGS. 3A and 3B are illustrating the manner in which the locking meansshown in FIGS. 1 and 2 is disengaged from the gripper head when thesleeve is brought to engagement with the locking shoulder of the gripperhead.

FIGS. 4A, 4B and 4C are illustrating the manner in which the inner coretube with the locking means is lowered by the gripper head, as well asthe manner in which the gripper head is released and lifted.

FIG. 5 is a cross-sectional view of a second embodiment of theinvention, illustrating particularly a modified positioning mechanism.

Referring to FIG. 1, the illustrated releasing device is primarilyintended for use in conjunction with a catching device consisting of twomain parts, viz a latch I rotatable on a shaft pivot 7 and provided witha locking and gripping shoulder 14, and a gripper head 2 with a grippershoulder 20, a gripper head rod 23 attached to said gripper head 2, anda dis placeable releasing sleeve 12. The lowermost end of the sleeve 12is provided with a flange 17, the upper edge of which is bevelled. Theuppermost end of the sleeve 12 is provided with recesses 15 and 16 foraccommodating a screw 8.

The sliding sleeve is intended to be brought to a rest position, i.e.the sleeve is brought back from the gripping shoulder 2a, and to bepositioned in this position by rotating the sleeve to the right andupwards, as seen on. the drawing, against the forces of a torsion spring13 and a compression spring 19, so that the screw 8 is accommodated inthe recess 16. The locked rest position is illustrated in FIG. 2A. Inthe free position, illustrated in FIG. 2C, the sleeve can be displacedfrom its upper rest position, as is shown in FIG. 3A, the screw 8 beingaccommodated in the recess 15, to a lower position as is shown in FIG.3B, the flange 17 thereby engaging the locking shoulder 20 of thegripper head.

When it is desirable to pick up the :inner core tube owing to thebottoming of the core samplewhich is detected on the surface by amanometer (not shown) which indicates an increase flushing waterpressure-the gripper head 2 is brought down through the bore tube 11,the releasing sleeve 12' thereby being fixed in its rest position inaccordance with FIGS. 2A and 3A. The gripper head slides over thebevelled locking shoulder 14 of the locking means 1, the locking meansthereby in this case simultaneously rotates on the pivot 7 so that alower shoulder 9 disengages the recess 10 of the outer tube 5. In orderto enable the head 2 to more easily move away the shoulder 14 a weight18 of massive steel is provided in the bottom end of the wire. The innertube can now be lifted since the head 2 engages the shoulder 2a beneaththe shoulder 14.

However, it may occur that the inner tube for some reason has jammed inthe outer tube so that it is impossible to lift the inner tube in thismanner. For enabling at least the very gripper head and the wire to belifted a biased compression spring 19 is provided, such as a package ofcup springs, so that the screw 8 can be pulled away out of its lockingengagement with the recess 16 (shown in FIGS. 2A, 2B and 2C) when thepulling force on the wire exceeds a predetermined value. The slidingsleeve 12 thereby rotates clockwise a quarter of a turn by the action ofthe torsion spring 13, the sleeve simultaneously falling against theupper surface of the shoulder 14. By removing the pulling force on thewire and by means of the force exerted by the weight 18 one can get theflange 17 of the sliding sleeveto slide over the shoulder 14 so that theflange gets the position shown in FIG. 3A. As is shown the upper portionof the sliding sleeve thereby rests on the housing 4 of the lockingmeans. When the wire is again stretched the flange 17 will be positionedover the head 2, and since its upper edge is bevelled the flange 17 aswell as the head 2 will easily slide past the shoulder 14, therebyenabling the lifting, such is illustrated in FIG. 3B.

Boreholes of the present type are usually filled with water, and inorder to bring the inner core tube downwards in the borehole one simplylets the core tube sink downwards in the hole, the water giving thedesired damping of the velocity of fall. However, if the borehole isdrained, the inner core tube must be lowered, and in that case thereleasing device in accordance with the invention can advantageouslyalso be used.

Thus, when a new inner tube shall be lowered the sliding sleeve is inits nonlocked position, and the operational sequence is then inaccordance with FIGS. 4A, 4B and 4C. In lowering the tube the gripperhead 2 with the shoulder 2a hence is in engagement with the bottomsurface of the shoulder 14. Upon the bottoming of the inner tube thegripper head 2 is further lowered a little so that the sleeve 12 isengaging the upper edge of the housing 4, the position of which isadapted in such a manner that also the flange 17 has now slid over theshoulder 14. If the wire is new again stretched the flange 17 as well asthe head 2-as is explained in conjunction with FIGS. 3A and 3B-willslide upwards over the shoulder 17 because of the bevelling of theflange. The locking means I thereby swings on the pivot 7 owing to thepressure of a wire spring 3. and the shoulder 9 engages the recess 10and thus hinders any upwards movement of the inner tube during theboring operation. I

FIG. 5 illustrates a second embodiment in which the positioningmechanism consists of an O-ring 20 lying in a comparatively deep groove21 in the releasing sleeve 12, the O ring cooperating with a shallowgroove 24 in the housing 25 in the rest position of the releasingsleeve. On a pulling force on the wire exceeding the weight of the innercore tube the sleeve 12 gets loose and sinks downwards towards theshoulder 2a in substantially the same manner as in the embodiment shownin FIGS. 1-4. For enabling the O-ring 20 to be replaced in the housing25 without being damaged a tapering 22 is provided in the housing 25.

The invention is not limited to the embodiments shown and described butcovers any other embodiment within the scope of the claims.

I claim:

1. A releasing device for releasing a locking mechanism in a catchingdevice which is intended to connect the wire with the inner core tube inwire line core drills in order to enable lifting and also lowering ofthe inner core tube, the locking mechanism having a gripper headconnected with the wire, the gripper head being provided with a lockingshoulder behind which a latch connected with the inner core tube isintended to engage and lock to perform said connection, characterized bya releasing sleeve which in its normal rest position is brought back adistance from the locking shoulder of the gripper head to release thelocking shoulder, the releasing sleeve being retainable in this positionby means of a positioning mechanism which is releasable by applying apredetermined pulling force to the wire, said pulling force having adirection away from the inner core tube and exceeding the weight of theinner core tube, the releasing sleeve upon such releasing of thepositioning mechanism being provided to be displaced unobstructedlytowards the gripper head and to engage the locking shoulder of thegripper head, thereby moving away the latch and said positioningmechanism including a torsion spring, one end of which is fastened to agripper head rod attached to the gripper head, the releasing sleevebeing slidably mounted on said rod, and the other end of which isfastened to the releasing sleeve, the upper end edge of the releasingspring is provided with a locking recess in which a positioning meansattached to the gripper head rod is intended to be accommodated for thepositioning of the releasing sleeve after same in its brought backposition is rotated to provide the desired biasing of the torsionspring, an axially active compression spring is provided on the gripperhead rod in order to retain the positioning means in fixed position inthe recess and to give way for enabling the removal of the positioningmeans from the recess and thereby to unbias the torsion spring upon awire pulling force which is directed away from the inner core tube andwhich substantially exceeds the weight of the inner core tube.

2. A releasing device for releasing a locking mechanism in a catchingdevice which is intended to connect the wire with the inner core tube inwire line core drills in order to enable lifting and also lowering ofthe inner core tube, the locking mechanism having a gripper headconnected with the wire, the gripper head being provided with a lockingshoulder behind which a latch connected with the inner core tube isintended to engage and lock to perform said connection, characterized bya releasing sleeve which in its normal rest position is brought back adistance from the locking shoulder of the gripper head to release thelocking shoulder, the releasing sleeve being retainable in this positionby means of a positioning mechanism which is releasable by applying apredetermined pulling force to the wire, said pulling force having adirection away from the inner core tube and exceeding the weight of theinner core tube, the releasing sleeve upon such releasing of thepositioning mechanism being provided to be displaced unobstructedlytowards the gripper head and to engage the locking shoulder of thegripper head, thereby moving away the latch and said positioningmechanism including an O-ring provided in a groove in the releasingsleeve and positioned in an inactive position by engagement in a shallowgroove in a housing in which the wire is fastened, said O-ring givingway to enable the displacing of the sleeve towards the shoulder of thegripper head upon a certain wire pulling force which is directed awayfrom the inner core tube and which substantially exceeds the weight ofthe inner core tube.

In colu myi 3 lin'e 3 7 the word" "spring" should Signed andsealed'this'zevth day of May 1973.

(SEAL) ROBERT GOTTSCHALK Commissioner of Paten Attest z EDWARDM.FLETCHE1R,JR. Attesting Officer

1. A releasing device for releasing a locking mechanism in a catchingdevice which is intended to connect the wire with the inner core tube inwire line core drills in order to enable lifting and also lowering ofthe inner core tube, the locking mechanism having a gripper headconnected with the wire, the gripper head being provided with a lockingshoulder behind which a latch connected with the inner core tube isintended to engage and lock to perform said connection, characterized bya releasing sleeve which in its normal rest position is brought back adistance from the locking shoulder of the gripper head to release thelocking shoulder, the releasing sleeve being retainable in this positionby means of a positioning mechanism which is releasable by applying apredetermined pulling force to the wire, said pulling force having adirection away from the inner core tube and exceeding the weight of theinner core tube, the releasing sleeve upon such releasing of thepositioning mechanism being provided to be displaced unobstructedlytowards the gripper head and to engage the locking shoulder of thegripper head, thereby moving away the latch and said positioningmechanism including a torsion spring, one end of which is fastened to agripper head rod attached to the gripper head, the releasing sleevebeing slidably mounted on said rod, and the other end of which isfastened to the releasing sleeve, the upper end edge of the releasingspring is provided with a locking recess in which a positioning meansattached to the gripper head rod is intended to be accommodated for thepositioning of the releasing sleeve after same in its brought backposition is rotated to provide the desired biasing of the torsionspring, an axially active compression spring is provided on the gripperhead rod in order to retain the positioning means in fixed position inthe recess and to give way for enabling the removal of the positioningmeans from the recess and thereby to unbias the torsion spring upon awire pulLing force which is directed away from the inner core tube andwhich substantially exceeds the weight of the inner core tube.
 2. Areleasing device for releasing a locking mechanism in a catching devicewhich is intended to connect the wire with the inner core tube in wireline core drills in order to enable lifting and also lowering of theinner core tube, the locking mechanism having a gripper head connectedwith the wire, the gripper head being provided with a locking shoulderbehind which a latch connected with the inner core tube is intended toengage and lock to perform said connection, characterized by a releasingsleeve which in its normal rest position is brought back a distance fromthe locking shoulder of the gripper head to release the lockingshoulder, the releasing sleeve being retainable in this position bymeans of a positioning mechanism which is releasable by applying apredetermined pulling force to the wire, said pulling force having adirection away from the inner core tube and exceeding the weight of theinner core tube, the releasing sleeve upon such releasing of thepositioning mechanism being provided to be displaced unobstructedlytowards the gripper head and to engage the locking shoulder of thegripper head, thereby moving away the latch and said positioningmechanism including an O-ring provided in a groove in the releasingsleeve and positioned in an inactive position by engagement in a shallowgroove in a housing in which the wire is fastened, said O-ring givingway to enable the displacing of the sleeve towards the shoulder of thegripper head upon a certain wire pulling force which is directed awayfrom the inner core tube and which substantially exceeds the weight ofthe inner core tube.